1. Field of the Invention
The present invention relates to a pipe coupling socket which uses a ball valve as a valving element and to or from which a plug can be attached or detached speedily and easily, and more particularly, to a pipe coupling socket suited for the connection between an air tool or the like and piping.
2. Description of the Related Art
Conventional pipe coupling sockets of this type are described in Jpn. Pat. Appln. KOKAI Publication No. 11-108279 and U.S. Pat. No. 3,423,063, for example.
If a plug is inserted into a plug inlet of the pipe coupling socket described in Jpn. Pat. Appln. KOKAI Publication No. 11-108279, in connecting the plug, a plug connecting sleeve and a valve control sleeve, having so far been retreated, advance. Thereupon, the plug is locked by means of the plug connecting sleeve, and a valve is opened by means of the valve control sleeve. In disconnecting the valve, the valve control sleeve is retreated, the valve is closed in the middle of the retreat, and a fluid in the plug is discharged to the outside. If the valve control sleeve is retreated further, the plug connecting sleeve retreats to unlock the plug, whereupon the plug can be disconnected from the pipe coupling socket.
If a plug is inserted into a plug inlet of the pipe coupling socket described in U.S. Pat. No. 3,423,063, in connecting the plug, on the other hand, a plug connecting sleeve, having so far been retreated, advances to lock the plug. If a valve control sleeve is advanced thereafter, the valve is opened. In disconnecting the plug, the valve is closed by retreating the valve control sleeve, and a fluid in the plug is discharged to the outside. If the plug connecting sleeve is retreated thereafter, the plug is unlocked, whereupon the plug can be disconnected from the pipe coupling socket.
Further, either of the pipe coupling sockets described in Jpn. Pat. Appln. KOKAI Publication No. 11-108279 and U.S. Pat. No. 3,423,063 is designed so that the valve control sleeve cannot be advanced, that is, the valve cannot be opened, unless the plug control sleeve is advanced. Means for holding the plug control sleeve in the retreated position shares lock balls with lock means for locking the plug. When the plug is not connected, the plug control sleeve engages the lock balls on the centrifugal side and is prevented from advancing. As the lock balls move to the centripetal direction when the plug is connected, the engagement is canceled, whereupon the plug control sleeve advances.
These pipe coupling sockets may be used for the connection of air piping and an air tool. In moving the air tool to another neighboring job site, regarding the pipe coupling socket described in Jpn. Pat. Appln. KOKAI Publication No. 11-108279, the plug connecting sleeve also retreats to cause the plug to be disconnected inevitably if the valve control sleeve is retreated to close the valve. Thus, the pipe coupling socket and the plug cannot be connected with the valve closed. Therefore, the plug may be either kept connected or disconnected as the tool is moved. In the former case, the valve is open, so the air tool may be accidentally actuated and cause injury while the air tool is being moved. Although the latter case is free from this problem, it is subject to a problem that the plug must be connected again at a destination, which is troublesome.
Since the valve control sleeve that is advanced to open the valve is allowed to retreat, moreover, the valve control sleeve may possibly run against some surrounding obstacles and retreat during the operation of the air tool, thereby causing the valve and the plug to be closed and disconnected, respectively.
In the case of the pipe coupling socket described in U.S. Pat. No. 3,423,063, furthermore, the pipe coupling socket and the plug can be connected in a manner such that only the valve control sleeve is retreated to close the valve. Since the valve control sleeve can advance, however, there is a problem that the valve control sleeve may possibly run against some surrounding obstacles and advance as the air tool moves, thereby causing the valve to open.
Further, either of the pipe coupling sockets described in Jpn. Pat. Appln. KOKAI Publication No. 11-108279 and U.S. Pat. No. 3,423,063 shares the same lock balls with the lock means for locking the plug as means for holding the plug control sleeve in the retreated position. Therefore, the lock balls may possibly move to the centripetal direction with the plug connected only partially to a pipe coupling. In this case, the plug control sleeve inevitably advances despite the partial connection of the plug, thus the valve control sleeve is unavoidably allowed to advance.
An object of the present invention is to provide a pipe coupling socket provided with lock means that prevents the advance and retreat of a valve control sleeve and a plug connecting sleeve, whereby safety is improved.
Another object of the present invention is to provide a pipe coupling socket in which the advance of a plug connecting sleeve is prevented so that a valve cannot be opened by means of a valve control sleeve if valve connection is partial, whereby safety is improved.
Another object of the present invention is to provide a pipe coupling socket in which seal valve-seats are prevented from being pressed to the ball valve under a fluid pressure. This ensures the durability of the seal valve-seats and the perfection of sealing.
In order to achieve the above objects, the invention according to claim 1 is a pipe coupling socket having a piping junction at one end thereof and a plug inlet at the other end, in which a piping passage and the plug inlet are internally connected by means of a through passage of a built-in ball valve, comprising: a socket body having therein a valve chamber, one end of which communicates with the piping passage and the other end of which communicates with the plug inlet, the ball valve located for rotation in the valve chamber, and a valve control sleeve which is fitted on the outer periphery of the socket body and which advances to open the ball valve and retreats to close the ball valve; a locking element which is supported on the distal end portion of the socket body for movement in the centripetal and centrifugal directions and engages an engaging groove formed on the outer periphery of a plug inserted in the plug inlet, thereby locking the plug; a plug connecting sleeve which is fitted on the distal-side outer periphery of the socket body and which advances to move the locking element to the centripetal direction, thereby locking the plug, and retreats to allow the locking element to move to the centrifugal direction, thereby unlocking the plug; first lock means which prevents the valve control sleeve from advancing when the plug connecting sleeve is situated in a retreated position; and second lock means which prevents the retreat of the plug connecting sleeve and the advance of the valve control sleeve when the plug connecting sleeve and the valve control sleeve are situated in an advanced position and a retreated position, respectively, and third lock means which prevents the retreat of the plug connecting sleeve and the valve control sleeve when the plug connecting sleeve and the valve control sleeve are situated in their respective advanced positions.
According to this configuration, the first lock means can prevent the valve control sleeve from advancing when the plug connecting sleeve is situated in the retreated position, the second lock means can prevent the retreat of the plug connecting sleeve and the advance of the valve control sleeve when the plug connecting sleeve and the valve control sleeve are situated in the advanced position and the retreated position, respectively, and the third lock means can prevent the retreat of the plug connecting sleeve and the valve control sleeve when the plug connecting sleeve and the valve control sleeve are situated in their respective advanced positions.
Preferably, the plug connecting sleeve is prevented from rotating in the circumferential direction and allowed to advance when in the retreated position, and is allowed to rotate in the circumferential direction to be prevented from retreating when in the advanced position, the rear end of the plug connecting sleeve having notches formed at given spaces in the circumferential direction, the notches being fitted with first lock balls for movement in the centripetal and centrifugal directions, the first lock balls moving back and forth as the plug connecting sleeve moves back and forth and moving in the circumferential direction with rotation. The outer peripheral surface of the socket body is formed having fitting recesses circumferentially fitted with the first lock balls of the plug connecting sleeve in the advanced position and having a depth for movement to the centripetal direction, the first lock balls being situated on the centripetal direction when the first lock balls are fitted in the fitting recesses, the first lock balls being situated on the centrifugal direction when the plug connecting sleeve is in the retreated position and when the plug connecting sleeve is situated in the advanced position and rotated so that the first lock balls are disengaged from the fitting recesses, the valve control sleeve in the retreated position being prevented from advancing when the plug connecting sleeve is in the retreated position in this state, and the valve control sleeve and the plug connecting sleeve being prevented from retreating when the plug connecting sleeve and the valve control sleeve are in the advanced position. The inner peripheral surface of the valve control sleeve has, on the distal end side thereof, a convex portion which extends in the circumferential direction and has first retaining step portions which engage the first lock, balls when the first lock balls are on the centrifugal side with the plug connecting sleeve in the advanced position, the convex portion is formed having moving grooves in positions corresponding to the fitting recesses in the outer peripheral surface of the socket body, depending on the distance covered by the movement of the plug connecting sleeve, the first lock balls in the centrifugal side being movable in the moving grooves, the moving grooves having, at the bottom thereof, second retaining step portions to which the first lock balls are anchored when the plug connecting sleeve is in the retreated position. Further, the convex portion is formed further having a first lock ball engaging groove which extends in the circumferential direction behind the moving grooves and is engaged by the first lock balls when first lock balls are on the centrifugal side. The first lock balls on the centrifugal side and the second retaining step portions at the bottom of the moving grooves of the valve control sleeve constitute the first lock means, the first lock balls on the centrifugal side and the first retaining step portions of the valve control sleeve constitute the second lock means; the first lock balls on the centrifugal side and the first lock ball engaging groove of the valve control sleeve constitute the third lock means, and the effect of locking by the first, second, and third lock means is removed when the first lock balls are fitted in the fitting recesses in the outer peripheral surface of the socket body and situated on the centripetal side.
According to this configuration, the second lock means, which prevents the retreat of the plug connecting sleeve and the advance of the valve control sleeve when the plug connecting sleeve and the valve control sleeve are situated in the advanced position and the retreated position, respectively, and the third lock means, which prevents the retreat of the plug connecting sleeve and the valve control sleeve when the plug connecting sleeve and the valve control sleeve are situated in their respective advanced positions, can be manipulated by simple operation such that the plug connecting sleeve is rotated in the circumferential direction.
Preferably, the distal end portion of the socket body is fitted with a plurality of second lock balls which are arranged in the circumferential direction behind the locking element for movement in the centripetal and centrifugal directions, the socket body is fitted with a first collar for movement, the first collar in an advanced position supporting and situating the second lock balls on the centrifugal side in a manner such that a part of each second lock ball projects from the outer peripheral surface of the socket body and retreating to release the second lock balls from the support, thereby allowing the second lock balls to sink into the socket body, the first collar being urged in the advancing direction by means of a spring so that the first collar retreats as a plug is inserted therein; the plug connecting sleeve has, on the distal end side of the inner peripheral surface thereof, a plug unlocking recess which extends in the circumferential direction and allows the locking element to move to the centrifugal direction, the plug unlocking recess being followed in the circumferential direction by a taper step portion, which presses and moves the locking element to the centripetal direction, and a plug lock projection, which holds down moved to the centripetal direction, the plug lock projection being followed in the circumferential direction by a second lock ball engaging groove in which the second lock balls are fitted; the plug unlocking recess is situated in the position of the locking element and is allowed to move to the centrifugal direction of the locking element when the second lock balls are on the centrifugal side with the plug connecting sleeve in the retreated position, the second lock balls engaging the second lock ball engaging groove, thereby preventing the advance of the plug connecting sleeve; and the locking element moved to the centrifugal direction in the process of plug insertion engages a step portion at the bottom of the plug unlocking recess of the plug connecting sleeve so that the plug connecting sleeve can advance when the first collar retreats to allow the second lock balls to move to the centripetal direction and be disengaged from the second lock ball engaging groove as the plug is inserted further.
In connecting the plug, according to this configuration, the second lock balls are disengaged from the second lock ball engaging groove after the locking element first engages the taper step portion, the plug connecting sleeve is allowed to advance after the locking element engages the plug. In disconnecting the plug, moreover, the locking element first engages the taper step portion to prevent the advance of the plug connecting sleeve as the plug connecting sleeve is retreated to draw out the plug. Then, the second lock balls engage the second lock ball engaging groove, and thereafter, the locking element is disengaged from the taper step portion. Therefore, there is no possibility of the plug connecting sleeve advancing with the plug not connected owing to partial connection of the plug or the like. Thus, the valve control sleeve cannot advance either, so that the ball valve cannot be opened with the plug not connected.
Preferably, moreover, the respective openings of the piping passage of the piping junction and the plug inlet, which open on the valve chamber side of the socket body, are provided individually with annular rubber seal valve-seats which coaxially face each other across the through passage of the ball valve in an open position and are elastically pressed to the outer peripheral wall of the ball valve, the openings being further provided individually with stoppers which prevent the annular rubber seal valve-seats from being pressed to the ball valve under an internal fluid pressure.
If the annular rubber seal valve-seats, which are elastically pressed to the outer peripheral wall of the ball valve, are subjected to the internal fluid pressure, according to this configuration, the stoppers prevent them from being deformed and from being pressed to the ball valve. Thus, the durability of the annular rubber seal valve-seats and the perfection of sealing can be ensured.
Other objects, features, and advantages of the present invention will be more apparent from the ensuing detailed description taken in connection with the accompanying drawings.